Season 05, Episode 21:
Necromancing the Stone
Piper summons Grams for Wyatt's Wiccaning ceremony. Grams is surprised to find that he is a boy. She plans to summon every matriarch since the witch trials and warns Piper about the Necromancer, who had attacked during Patty's ceremony.
A minion of the ghostly Necromancer presents him with a fairy in a glass jar — and he has deliberately not punched holes in the lid. The fairy dies and the Necromancer absorbs her escaping spirit, becoming more solid. Jason is going to Hong Kong for the next six months and wants to take Phoebe with him. Phoebe is reluctant but Jason offers her the use of the corporate jet. Meanwhile, Paige casts a truth spell on Nate and discovers that he has no problem with her being a witch, but the spell also reveals that he is married with children.
Piper is with Grams reading the Book of Shadows on the Necromancer, and finds marginal notes in Grams's handwriting. Grams tells Piper what she knows of the Necromancer — he wants to be resurrected for good and the spirits of the Halliwell witches would be perfect for that. Grams, Piper and Paige go to the Necromancer's lair and the sisters are surprised when the Necromancer calls her "Penny" in a pleasant tone. Grams blasts him with a spell and Paige throws a potion; the Necromancer bursts into flames. Paige says he can't be vanquished but (still upset over Nate) that they had "sent his sorry male [posterior] back to the Spirit Realm". The minion casts a spell and the Necromancer returns, in ghostly form. He says he had once been in love with Grams. The minion tells the Necromancer about Wyatt and the Wiccaning.
Meeting the Necromancer has evoked Grams's feelings about men. She is worried that a man cannot handle magic and that Wyatt will turn evil. She is unwilling to do the Wiccaning and won't even hold Wyatt.
Grams argues with Piper and Phoebe. At that time, the minion shimmers in and attacks. Grams tries to fight back but he waves a hand and flips Grams backward into the arms of the Necromancer. Piper vanquishes the minion, but the Necromancer vanishes, taking Grams with him. The Necromancer tries to convince Grams to summon the matriarchs; their spirits could fully resurrect them both.
The sisters are discussing what they should do. While Phoebe reads the Necromancers entry in the Book, looking for a weakness, Piper mentions the trivia about him that Grams had written on the pages. Phoebe, who once wrote trivia on Cole in the Book, suddenly realizes that Grams was the Necromancer's lover. They find the ghost-banishing spell in the Book; one must be dead to use it, but Grams is a ghost. They summon Grams, but she is under the Necromancer's spell.
The Necromancer soon appears. Grams starts the spell to summon the matriarchs, but Paige says a spell to free Grams's will. Grams admits to loving the Necromancer but she loves her family more. She says the banishment spell. Jason regrets having sprung his offer to go to Hong Kong with Phoebe. Phoebe, however, at first, wants to come lest she end up bitter like Grams. But when she meets Jason at the airport, she is carrying no bags. She has decided that her place is with her sisters, just for now.
Grams has changed her mind about Wyatt and is willing to do the ceremony.